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Anthony J. Gaston - One of the best experts on this subject based on the ideXlab platform.
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The Authors
2020Co-Authors: Anthony J. Gaston, Vicki L. Friesen, G. Ibarguchi, Ibarguchi@queensu.ca GabrielaAbstract:Many seabirds exhibit high natal philopatry despite their extreme dispersal ability and delayed reproduction, and some exhibit phenotypic clustering in colonies and fostering or adoption of neighbouring chicks. Previous investigations of kinship in a small Thick-Billed Murre colony Uria lomvia (Alcidae) in Norway revealed high relatedness among breeders on cliff ledges. To investigate the presence of kin groups and within-colony genetic sub-structuring elsewhere, we investigated kinship within a larger Murre colony on Coats Island, Nunavut, Canada. Morphological (five characters) and genetic data (five microsatellite loci and a fragment of the mitochondrial cytochrome b gene) were analysed. Strong morphological differentiation was found among ledges. Genetic structuring was overall weak but significant at the coarse scale for males among ledges and on the east vs. the west side of the colony. Global spatial autocorrelation analyses did not detect consistent, widespread spatial patterns, although local 2D analyses provided some evidence of a tendency for larger neighbourhood sizes for females and a broad range of small to large neighbourhoods for males. Average withinledge relatedness was low overall, but ranged widely from slightly unrelated to greater than the level of cousins in both sexes. Kin-level relationships occurred on ledges more frequently for same-sex groups than expected by chance, suggesting that recruiting breeders (especially females) avoid or are unable to settle directly adjacent to relatives particularly of the opposite sex. Behavioural studies of natal dispersal of Murres at Coats I. indicating that both sexes are highly philopatric, but that up to one-fifth of females may disperse, are concordant with this study. Overall, structuring was weaker than in Norway, and may be explained in part by genetic marker and sampling artifacts, and by the lack of genetic equilibrium suspected in the much larger Canadian Arctic colony. Natal philopatry may be an important factor driving the diversification of seabirds and kin groups in other colonies and species and may be more widespread than is currently acknowledged. Natal site fidelity (natal philopatry) can strongly impact the genetic structure of populations. Philopatry over many generations can promote genetic structure both among-and within-populations, and the formation of kin groups. Within small groups evolution can proceed at a faster rate due to non-random mating (Kingston an
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VARIATION IN EGG SIZE AND LAYING DATE IN Thick-Billed Murre POPULATIONS BREEDING IN THE LOW ARCTIC AND HIGH ARCTIC
2020Co-Authors: Mark J Hipfner, Anthony J. Gaston, Grant H GilchristAbstract:Abstract. We used data collected across 28 years to compare how timing of laying and egg size respond to environmental variability in two low-arctic and two higharctic Thick-Billed Murre (Uria lomvia) populations. Ice conditions strongly affect food availability to marine birds in the Arctic, and the percentage of the sea's surface covered by ice within 300 km of the breeding colony varied more among years near the start of laying at our high-arctic study colonies (Prince Leopold and Coburg Islands, Nunavut, Canada) than at our low-arctic study colonies (Coats and Digges Islands, Nunavut). However, mean values differed little. These results indicate that Thick-Billed Murres breeding in the High Arctic experience more variable ice conditions, but not necessarily more severe ice conditions, during the period of egg formation. In response, both median laying date and mean egg size varied more among years at high-arctic than at low-arctic colonies. Several lines of evidence suggested that the variation was a result of within-female effects, i.e., phenotypic plasticity rather than different individuals breeding in years in which environmental conditions differed. Previous studies have shown that Thick-Billed Murres lay eggs later in years of heavier ice coverage, especially in the High Arctic where ice conditions can be severe, and only in the High Arctic was later laying associated with reduced egg size. The relationship tended towards a negative asymptote suggesting that each female may have her own minimum egg size. Our results show that Thick-Billed Murres that inhabit a more variable environment display greater variability in life-history traits. More generally, they offer insight into mechanisms linking environmental heterogeneity to phenotypic variation in life-history traits. Key words: egg size, environmental conditions, laying date, plasticity, Thick-Billed Murre, Uria lomvia. Variación en el Tamaño del Huevo y la Fecha de Puesta en Poblaciones Reproductivas de Uria lomvia en el Á rtico Bajo y el Á rtico Alto Resumen. Empleamos datos colectados a lo largo de 28 años (1975-2002) para determinar cómo el ajuste temporal de la puesta y del tamaño del huevo responde a la variabilidad ambiental en dos poblaciones del Á rtico bajo y dos poblaciones del Á rtico alto de Uria lomvia. Las condiciones del hielo afectaron fuertemente la disponibilidad de alimentos para las aves marinas en el Á rtico. El porcentaje de la superficie del mar cubierta por hielo a menos de 300 km de la colonia reproductiva varió más entre años cerca del inicio de la puesta en nuestras colonias de estudio del Á rtico alto (Islas Prince Leopold y Coburg, Nunavut, Canadá) que en nuestras colonias de estudio del Á rtico bajo (Islas Coats and Digges, Nunavut). Sin embargo, los valores medios difirieron poco. Estos resultados indican que los individuos de Uria lomvia que crían en el Á rtico alto experimentan condiciones de hielo más variables, pero no necesariamente más severas, durante el período de la formación del huevo. Como respuesta, tanto la fecha mediana de puesta y la media del tamaño del huevo variaron más entre años en las colonias del Á rtico alto que en las del Á rtico bajo. Varias líneas de evidencia sugirieron que esta variación fue el resultado de variaciones propias de las hembras (i.e., plasticidad fenotípica) y no de variación entre individuos diferentes que criaron en años en los cuales las condiciones ambientales difirieron. Estudios previos han mostrado que Uria lomvia realiza su puesta más tarde en los años de mucha cobertura de hielo, especialmente en el Á rtico alto, donde las condiciones de hielo pueden ser severas, y sólo en el Á rtico alto la demora de la puesta se asoció con una reducción del tamaño del huevo. La relación tendió hacia una asíntota negativa, sugiriendo que cada hembra podría tener su propio tamaño mínimo del huevo. Nuestros resultados muestran que los individuos de Uria lomvia que habitan un ambiente más variable muestran mayor variabilidad en los rasgos de historia de vida. De modo más general, nuestros resultados ofrecen información sobre los mecanismos que vinculan la heterogeneidad ambiental con la variación fenotípica en los rasgos de historia de vida
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Climate Influence on Legacy Organochlorine Pollutants in Arctic Seabirds
2019Co-Authors: Karen L. Foster, Anthony J. Gaston, Birgit M Braune, Mark L. MalloryAbstract:Changing climate can influence the transport of chemical pollutants into Arctic regions and their fate once there. However, the influence of weather or climate variables on organochlorine accumulation in Arctic wildlife, including seabirds, and associated time scale are poorly understood. We assessed the interannual relationships between a suite of weather/climate variables for time lags of 0 to 10 yr and organochlorine pollutant concentrations spanning 1975–2014 in eggs of two seabird species (northern fulmar Fulmarus glacialis, Thick-Billed Murre Uria lomvia) that breed in the Canadian High Arctic. The majority of variability in the data was associated with declining organochlorine emissions (up to 70.2% for Murres and 77.4% for fulmars). By controlling for emissions using principal component ordination and general linear modeling, correlations with the North Atlantic Oscillation (NAO) were found for fulmars and with rainfall for Murres, after a time lag of 4–9 yr between weather/climate conditions and egg collection. Our results suggest that with increasingly NAO+ conditions and increasing rainfall associated with climate change, concentrations of certain organochlorines such as hexachlorobenzene and p,p′-DDE have increased, dependent on seabird species and ecology as well as partitioning characteristics of the chemical. Analysis of a truncated version of the data sets (2005–2014), consistent with typical time series lengths for environmental pollutants in Arctic wildlife, found correlations with precipitation for Murres but not with NAO for fulmars, suggesting that longer time series better elucidate relationships with broad-scale climate indices. Organochlorine pollutant data sets spanning 40 years, which is rare for Arctic wildlife, for two species of seabird were assessed, and the results highlight the association between weather/climate and pollutant accumulation in Arctic food webs and the critical role of ongoing monitoring to effectively elucidate these relationships
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migration and wintering of a declining seabird the thick billed Murre uria lomvia on an ocean basin scale conservation implications
Biological Conservation, 2016Co-Authors: Morten Frederiksen, Anthony J. Gaston, Grant H Gilchrist, Sebastien Descamps, Kjell Einar Erikstad, David Gremillet, Kasper Lambert Johansen, Yann Kolbeinsson, Jannie Fries LinnebjergAbstract:Pelagic seabirds are exposed to an array of potential threats during the non-breeding period, and effective management of these threats on a large scale requires knowledge of which populations winter where. Thick-Billed Murres (Uria lomvia) are emblematic of this conservation challenge, since they breed widely in the circumpolar Arctic, with many declining populations in the Atlantic. Threats facing Murres include hunting, oil spills, bycatch and oceanic change influencing prey availability. Previous knowledge of migration pathways was insufficient to estimate the composition of various wintering populations. We collated tracking data (light-based geolocation) of 320 Murres from 18 colonies in Canada, Greenland, Iceland, Svalbard and mainland Norway. Data were combined with breeding population counts to estimate the size and composition of wintering populations. The main wintering areas were off Newfoundland and Labrador, off West Greenland, and around Iceland. Winter areas were associated with the interface between High and Low Arctic ocean regimes. There was strong correspondence between wintering area and breeding population status: stable populations breeding in Canada and Northwest Greenland wintered mainly off Canada, whereas declining populations from Svalbard and Iceland wintered mainly off West Greenland and around Iceland. Many populations used distinct post-breeding areas, presumably for moulting; some of these areas were previously unknown. In some populations, there was a clear tendency for females to migrate south earlier than males, which accompany flightless fledglings when they leave the colony. Our study provides a key example of the urgency of coordinated, transoceanic management of vulnerable migratory species such as seabirds.
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Diel vertical migration of prey and light availability constrain foraging in an Arctic seabird
Marine Biology, 2015Co-Authors: Kyle Hamish Elliott, Anthony J. GastonAbstract:Studies of seabird–prey interactions often focus on biotic factors, such as prey abundance, seabird biomechanics and competition. In contrast, we examined the influence of abiotic factors, particularly weather, light and tide, on the diving behaviour of Thick-Billed Murre ( Uria lomvia ) foraging in the Canadian Low Arctic. We found little evidence that tide and weather influenced dive behaviour. As visual predators, light availability limits foraging opportunities; however, prey often surface at night so there may be a trade-off between increased food availability and reduced foraging ability during low-light conditions. Our data lent support to both ideas, as dive depth increased with light availability and the proportion of vertically migrating schooling prey was highest during sunup and sundown. There was no difference in dive depth between sexes outside the period of sundown; males, which forage at night, dove shallower than females in the late afternoon, which we suggest is because they specialize on shallow prey often caught at night. Apparently, adaptation for higher oxygen stores or lower oxygen consumption in deeper-diving females overrode any adaptation for improved vision in night-specialist males. We concluded that light availability interacted with prey vertical migration to impact underwater foraging abilities of breath-hold divers.
Grant H Gilchrist - One of the best experts on this subject based on the ideXlab platform.
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VARIATION IN EGG SIZE AND LAYING DATE IN Thick-Billed Murre POPULATIONS BREEDING IN THE LOW ARCTIC AND HIGH ARCTIC
2020Co-Authors: Mark J Hipfner, Anthony J. Gaston, Grant H GilchristAbstract:Abstract. We used data collected across 28 years to compare how timing of laying and egg size respond to environmental variability in two low-arctic and two higharctic Thick-Billed Murre (Uria lomvia) populations. Ice conditions strongly affect food availability to marine birds in the Arctic, and the percentage of the sea's surface covered by ice within 300 km of the breeding colony varied more among years near the start of laying at our high-arctic study colonies (Prince Leopold and Coburg Islands, Nunavut, Canada) than at our low-arctic study colonies (Coats and Digges Islands, Nunavut). However, mean values differed little. These results indicate that Thick-Billed Murres breeding in the High Arctic experience more variable ice conditions, but not necessarily more severe ice conditions, during the period of egg formation. In response, both median laying date and mean egg size varied more among years at high-arctic than at low-arctic colonies. Several lines of evidence suggested that the variation was a result of within-female effects, i.e., phenotypic plasticity rather than different individuals breeding in years in which environmental conditions differed. Previous studies have shown that Thick-Billed Murres lay eggs later in years of heavier ice coverage, especially in the High Arctic where ice conditions can be severe, and only in the High Arctic was later laying associated with reduced egg size. The relationship tended towards a negative asymptote suggesting that each female may have her own minimum egg size. Our results show that Thick-Billed Murres that inhabit a more variable environment display greater variability in life-history traits. More generally, they offer insight into mechanisms linking environmental heterogeneity to phenotypic variation in life-history traits. Key words: egg size, environmental conditions, laying date, plasticity, Thick-Billed Murre, Uria lomvia. Variación en el Tamaño del Huevo y la Fecha de Puesta en Poblaciones Reproductivas de Uria lomvia en el Á rtico Bajo y el Á rtico Alto Resumen. Empleamos datos colectados a lo largo de 28 años (1975-2002) para determinar cómo el ajuste temporal de la puesta y del tamaño del huevo responde a la variabilidad ambiental en dos poblaciones del Á rtico bajo y dos poblaciones del Á rtico alto de Uria lomvia. Las condiciones del hielo afectaron fuertemente la disponibilidad de alimentos para las aves marinas en el Á rtico. El porcentaje de la superficie del mar cubierta por hielo a menos de 300 km de la colonia reproductiva varió más entre años cerca del inicio de la puesta en nuestras colonias de estudio del Á rtico alto (Islas Prince Leopold y Coburg, Nunavut, Canadá) que en nuestras colonias de estudio del Á rtico bajo (Islas Coats and Digges, Nunavut). Sin embargo, los valores medios difirieron poco. Estos resultados indican que los individuos de Uria lomvia que crían en el Á rtico alto experimentan condiciones de hielo más variables, pero no necesariamente más severas, durante el período de la formación del huevo. Como respuesta, tanto la fecha mediana de puesta y la media del tamaño del huevo variaron más entre años en las colonias del Á rtico alto que en las del Á rtico bajo. Varias líneas de evidencia sugirieron que esta variación fue el resultado de variaciones propias de las hembras (i.e., plasticidad fenotípica) y no de variación entre individuos diferentes que criaron en años en los cuales las condiciones ambientales difirieron. Estudios previos han mostrado que Uria lomvia realiza su puesta más tarde en los años de mucha cobertura de hielo, especialmente en el Á rtico alto, donde las condiciones de hielo pueden ser severas, y sólo en el Á rtico alto la demora de la puesta se asoció con una reducción del tamaño del huevo. La relación tendió hacia una asíntota negativa, sugiriendo que cada hembra podría tener su propio tamaño mínimo del huevo. Nuestros resultados muestran que los individuos de Uria lomvia que habitan un ambiente más variable muestran mayor variabilidad en los rasgos de historia de vida. De modo más general, nuestros resultados ofrecen información sobre los mecanismos que vinculan la heterogeneidad ambiental con la variación fenotípica en los rasgos de historia de vida
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migration and wintering of a declining seabird the thick billed Murre uria lomvia on an ocean basin scale conservation implications
Biological Conservation, 2016Co-Authors: Morten Frederiksen, Anthony J. Gaston, Grant H Gilchrist, Sebastien Descamps, Kjell Einar Erikstad, David Gremillet, Kasper Lambert Johansen, Yann Kolbeinsson, Jannie Fries LinnebjergAbstract:Pelagic seabirds are exposed to an array of potential threats during the non-breeding period, and effective management of these threats on a large scale requires knowledge of which populations winter where. Thick-Billed Murres (Uria lomvia) are emblematic of this conservation challenge, since they breed widely in the circumpolar Arctic, with many declining populations in the Atlantic. Threats facing Murres include hunting, oil spills, bycatch and oceanic change influencing prey availability. Previous knowledge of migration pathways was insufficient to estimate the composition of various wintering populations. We collated tracking data (light-based geolocation) of 320 Murres from 18 colonies in Canada, Greenland, Iceland, Svalbard and mainland Norway. Data were combined with breeding population counts to estimate the size and composition of wintering populations. The main wintering areas were off Newfoundland and Labrador, off West Greenland, and around Iceland. Winter areas were associated with the interface between High and Low Arctic ocean regimes. There was strong correspondence between wintering area and breeding population status: stable populations breeding in Canada and Northwest Greenland wintered mainly off Canada, whereas declining populations from Svalbard and Iceland wintered mainly off West Greenland and around Iceland. Many populations used distinct post-breeding areas, presumably for moulting; some of these areas were previously unknown. In some populations, there was a clear tendency for females to migrate south earlier than males, which accompany flightless fledglings when they leave the colony. Our study provides a key example of the urgency of coordinated, transoceanic management of vulnerable migratory species such as seabirds.
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Changes in Food Web Structure Alter Trends of Mercury Uptake at Two Seabird Colonies in the Canadian Arctic
2014Co-Authors: Birgit M Braune, Grant H Gilchrist, Keith A Hobson, Anthony J. Gaston, Mark L. MalloryAbstract:Arctic ecosystems are changing in response to climate change and some Arctic food web structures are being affected in ways which may have potential consequences for the biomagnification of environmental contaminants. Here, we examined how a shift in diet of an Arctic seabird resulted in a change of trophic position and how that change affected exposure to mercury over time. The Thick-Billed Murre (Uria lomvia), which breeds in the eastern Canadian Arctic, has been monitored for diet and environmental contaminants at two colonies, one in northern Hudson Bay and one in the high Arctic. As a result of a change in diet, Murres breeding in Hudson Bay lowered their trophic position which, in turn, should affect their mercury exposure over time. After adjusting mercury concentrations in Murre eggs for trophic position, the temporal trend of mercury in Hudson Bay Murre eggs changed from nonsignificant to a significantly increasing trend. Valid trends can be deduced only when factors, such as diet, have been taken into account
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movements and wintering areas of breeding age thick billed Murre uria lomvia from two colonies in nunavut canada
Marine Biology, 2011Co-Authors: Anthony J. Gaston, David A. Fifield, Mark L. Mallory, Grant H Gilchrist, Gregory J. Robertson, William A. Montevecchi, April Hedd, Paul A. Smith, Laura Mcfarlane Tranquilla, Richard A. PhillipsAbstract:The non-breeding movements of marine birds were poorly known until recently, but this information is essential to understanding the risk to different geographical populations from events on the wintering grounds. We tracked the migration routes and wintering areas of Thick-Billed Murre Uria lomvia from two breeding colonies in eastern Canada: Coats Island in northern Hudson Bay and The Minarets, Baffin Island, during the period August 2007–May 2008 using geolocation loggers. Birds from The Minarets moved south rapidly post-breeding and wintered principally off Newfoundland and southern Labrador, or between Newfoundland and southern Greenland, remaining south of 55°N until at least the spring equinox. Those from Coats Island remained in Hudson Bay until at least mid-November, after which they moved rapidly through Hudson Strait to winter in southern Davis Strait and the northern Labrador Sea, mostly north of 55°N. Many individuals stayed throughout the winter in areas of heavy ice cover. Adults from the two colonies appear to be completely segregated in winter and those from Coats Island probably did not enter the area of the winter hunt in Newfoundland. Unexpectedly, some birds from The Minarets wintered in waters beyond the continental slope and outside the distribution of pack ice, demonstrating that particular individuals can be wholly pelagic throughout the winter. Coats Island birds returned through Hudson Strait as soon as open water areas became available in spring. Their sojourn in Hudson Bay coincided very closely with the occurrence of areas with <90% ice cover. In spite of the relatively large error in positions obtained from geolocation loggers, our results demonstrated the value of these devices by uncovering a number of previously unknown aspects of Thick-Billed Murre non-breeding ecology in the Northwest Atlantic. Comparison of the non-breeding ecology based on SST experienced in winter show that the winter niche is broader than hitherto assumed, demonstrating that separate populations may experience different selection in the face of climate change.
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ingested plastic in a diving seabird the thick billed Murre uria lomvia in the eastern canadian arctic
Marine Pollution Bulletin, 2010Co-Authors: Jennifer F Provencher, Anthony J. Gaston, Mark L. Mallory, Patrick D Ohara, Grant H GilchristAbstract:Plastic debris has become ubiquitous in the marine environment and seabirds may ingest debris which can have deleterious effects on their health. In the North Atlantic Ocean, surface feeding seabirds typically ingest high levels of plastic, while the diving auks which feed in the water column typically have much lower levels. We examined 186 Thick-Billed Murres from five colonies in the eastern Canadian Arctic for ingested plastic debris. Approximately 11% of the birds had at least one piece of plastic debris in their gastrointestinal tracts, with debris dominated by user plastics. This is the first report of ingested plastics in an auk species in Canada's Arctic, and the highest incidence of plastic ingestion to date for Thick-Billed Murres (Uria lomvia).
Kyle H. Elliott - One of the best experts on this subject based on the ideXlab platform.
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Seabird species vary in behavioural response to drone census
Scientific Reports, 2017Co-Authors: Émile Brisson-curadeau, Chantelle Burke, David Bird, Richard B. Sherley, David A. Fifield, Paul Pace, Kyle H. ElliottAbstract:Unmanned aerial vehicles (UAVs) provide an opportunity to rapidly census wildlife in remote areas while removing some of the hazards. However, wildlife may respond negatively to the UAVs, thereby skewing counts. We surveyed four species of Arctic cliff-nesting seabirds (glaucous gull Larus hyperboreus, Iceland gull Larus glaucoides, common Murre Uria aalge and Thick-Billed Murre Uria lomvia) using a UAV and compared censusing techniques to ground photography. An average of 8.5% of Murres flew off in response to the UAV, but >99% of those birds were non-breeders. We were unable to detect any impact of the UAV on breeding success of Murres, except at a site where aerial predators were abundant and several birds lost their eggs to predators following UAV flights. Furthermore, we found little evidence for habituation by Murres to the UAV. Most gulls flew off in response to the UAV, but returned to the nest within five minutes. Counts of gull nests and adults were similar between UAV and ground photography, however the UAV detected up to 52.4% more chicks because chicks were camouflaged and invisible to ground observers. UAVs provide a less hazardous and potentially more accurate method for surveying wildlife. We provide some simple recommendations for their use.
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windscapes shape seabird instantaneous energy costs but adult behavior buffers impact on offspring
Movement ecology, 2014Co-Authors: Kyle H. Elliott, Scott A Hatch, Anthony J. Gaston, Lorraine S Chivers, Lauren Bessey, Akiko Kato, Orla Osborne, Yan RopertcoudertAbstract:Windscapes affect energy costs for flying animals, but animals can adjust their behavior to accommodate wind-induced energy costs. Theory predicts that flying animals should decrease air speed to compensate for increased tailwind speed and increase air speed to compensate for increased crosswind speed. In addition, animals are expected to vary their foraging effort in time and space to maximize energy efficiency across variable windscapes. We examined the influence of wind on seabird (Thick-Billed Murre Uria lomvia and black-legged kittiwake Rissa tridactyla) foraging behavior. Airspeed and mechanical flight costs (dynamic body acceleration and wing beat frequency) increased with headwind speed during commuting flights. As predicted, birds adjusted their airspeed to compensate for crosswinds and to reduce the effect of a headwind, but they could not completely compensate for the latter. As we were able to account for the effect of sampling frequency and wind speed, we accurately estimated commuting flight speed with no wind as 16.6 ms−1 (Murres) and 10.6 ms−1 (kittiwakes). High winds decreased delivery rates of schooling fish (Murres), energy (Murres) and food (kittiwakes) but did not impact daily energy expenditure or chick growth rates. During high winds, Murres switched from feeding their offspring with schooling fish, which required substantial above-water searching, to amphipods, which required less above-water searching. Adults buffered the adverse effect of high winds on chick growth rates by switching to other food sources during windy days or increasing food delivery rates when weather improved.
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thyroid hormones correlate with resting metabolic rate not daily energy expenditure in two charadriiform seabirds
Biology Open, 2013Co-Authors: Kyle H. Elliott, Scott A Hatch, Anthony J. Gaston, Jorg Welcker, Vince P Palace, James F Hare, John R Speakman, Gary W AndersonAbstract:Thyroid hormones affect in vitro metabolic intensity, increase basal metabolic rate (BMR) in the lab, and are sometimes correlated with basal and/or resting metabolic rate (RMR) in a field environment. Given the difficulty of measuring metabolic rate in the field—and the likelihood that capture and long-term restraint necessary to measure metabolic rate in the field jeopardizes other measurements—we examined the possibility that circulating thyroid hormone levels were correlated with RMR in two free-ranging bird species with high levels of energy expenditure (the black-legged kittiwake, Rissa tridactyla, and Thick-Billed Murre, Uria lomvia). Because BMR and daily energy expenditure (DEE) are purported to be linked, we also tested for a correlation between thyroid hormones and DEE. We examined the relationships between free and bound levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) with DEE and with 4-hour long measurements of post-absorptive and thermoneutral resting metabolism (resting metabolic rate; RMR). RMR but not DEE increased with T3 in both species; both metabolic rates were independent of T4. T3 and T4 were not correlated with one another. DEE correlated with body mass in kittiwakes but not in Murres, presumably owing to the larger coefficient of variation in body mass during chick rearing for the more sexually dimorphic kittiwakes. We suggest T3 provides a good proxy for resting metabolism but not DEE in these seabird species.
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Effects of Climate-Induced Changes in Parasitism, Predation and Predator-Predator Interactions on Reproduction and Survival of an Arctic Marine Bird
2012Co-Authors: Anthony J. Gaston, Kyle H. ElliottAbstract:ABSTRACT. A detailed understanding of the processes and interactions within biological communities is needed to describe and predict the biological consequences of climate change. Global warming may affect biological communities at specific sites through changes in the species composition that follow changes in range, or through altered food web interactions caused by changes in phenology or behaviour. We describe the demographic consequences for a colonial nesting seabird, the Thick-Billed Murre (Uria lomvia), of exceptionally intense mosquito parasitism and predation by polar bears in a particular year. Increases in mosquito parasitism and bear predation are changes in behaviour rather than changes in range, and both caused unusual adult mortality and reproductive failure in Thick-Billed Murres. In the case of adult mortality, the effects of predation and parasitism were complementary, whereas in the case of reproductive failure, most birds affected by parasitism would in any case have subsequently lost their eggs to bear predation. The mosquito and bear activities had the secondary result of redirecting the attention of gulls and foxes, the usual predators of Murre eggs, towards scavenging carcasses and preying on eggs exposed by birds deserting their ledges. This diversion reduced the impact of gulls and foxes on the Murres and altered the spatial configuration of predation risk. Our observations emphasize the difficulty faced by ecologists in predicting the consequences of global warming even for simple and relatively well-studied ecosystems. Moreover, the net effect of combined parasitism and predation was much greater than reported previously, reducing overall colony productivity by 20 % and increasing adult mortality by 20%. If this effect happens every year, it will have population consequences
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Sex-specific behavior by a monomorphic seabird represents risk partitioning
Behavioral Ecology, 2010Co-Authors: Kyle H. Elliott, Anthony J. Gaston, Douglas CrumpAbstract:The presence of sex-stereotyped behavior in monomorphic animals, where there are no sexual differences in form to account for sexual differences in function, is often attributed to intraspecific competition or to differential parental investment. The possibility that the use of different behavioral strategies by each parent may increase reproductive success for both partners through risk partitioning is seldom considered. We studied Thick-Billed Murres (Uria lomvia), where the male exclusively feeds the offspring during the late chick rearing. During the period of biparental care, males fed on ‘‘risk-averse’’ prey (consistent across time and space; unitized risk ¼ 0.29), whereas females fed on ‘‘risk-prone’’ prey (risk ¼ 0.59). Males fed at night at 1 colony, during the day at 2 colonies, and there was no pattern at another colony. We suggest that these differences reflect the availability of risk-prone prey. Modeling suggested that mixed-risk pairs had higher success than ‘‘risky’’ or ‘‘riskless’’ pairs. Males accumulated reserves and reduced chick provisioning just prior to fledging. Thus, sex-specific patterns at 1 period (male-only care during postfledging) may have led to sex-specific patterns at earlier periods through the need for specialization in foraging habits and risk. We propose that risk partitioning may contribute to the prevalence of sex-specific behaviors in monomorphic animals and that patterns are likely context specific rather than species specific. Key words: risk aversion, sex-specific behavior, Thick-Billed Murre, Uria lomvia. [Behav Ecol]
Vicki L. Friesen - One of the best experts on this subject based on the ideXlab platform.
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The Authors
2020Co-Authors: Anthony J. Gaston, Vicki L. Friesen, G. Ibarguchi, Ibarguchi@queensu.ca GabrielaAbstract:Many seabirds exhibit high natal philopatry despite their extreme dispersal ability and delayed reproduction, and some exhibit phenotypic clustering in colonies and fostering or adoption of neighbouring chicks. Previous investigations of kinship in a small Thick-Billed Murre colony Uria lomvia (Alcidae) in Norway revealed high relatedness among breeders on cliff ledges. To investigate the presence of kin groups and within-colony genetic sub-structuring elsewhere, we investigated kinship within a larger Murre colony on Coats Island, Nunavut, Canada. Morphological (five characters) and genetic data (five microsatellite loci and a fragment of the mitochondrial cytochrome b gene) were analysed. Strong morphological differentiation was found among ledges. Genetic structuring was overall weak but significant at the coarse scale for males among ledges and on the east vs. the west side of the colony. Global spatial autocorrelation analyses did not detect consistent, widespread spatial patterns, although local 2D analyses provided some evidence of a tendency for larger neighbourhood sizes for females and a broad range of small to large neighbourhoods for males. Average withinledge relatedness was low overall, but ranged widely from slightly unrelated to greater than the level of cousins in both sexes. Kin-level relationships occurred on ledges more frequently for same-sex groups than expected by chance, suggesting that recruiting breeders (especially females) avoid or are unable to settle directly adjacent to relatives particularly of the opposite sex. Behavioural studies of natal dispersal of Murres at Coats I. indicating that both sexes are highly philopatric, but that up to one-fifth of females may disperse, are concordant with this study. Overall, structuring was weaker than in Norway, and may be explained in part by genetic marker and sampling artifacts, and by the lack of genetic equilibrium suspected in the much larger Canadian Arctic colony. Natal philopatry may be an important factor driving the diversification of seabirds and kin groups in other colonies and species and may be more widespread than is currently acknowledged. Natal site fidelity (natal philopatry) can strongly impact the genetic structure of populations. Philopatry over many generations can promote genetic structure both among-and within-populations, and the formation of kin groups. Within small groups evolution can proceed at a faster rate due to non-random mating (Kingston an
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outlier analyses to test for local adaptation to breeding grounds in a migratory arctic seabird
Ecology and Evolution, 2017Co-Authors: Anna Tigano, Gregory J. Robertson, Allison J Shultz, Scott V Edwards, Vicki L. FriesenAbstract:Investigating the extent (or the existence) of local adaptation is crucial to understanding how populations adapt. When experiments or fitness measurements are difficult or impossible to perform in natural populations, genomic techniques allow us to investigate local adaptation through the comparison of allele frequencies and outlier loci along environmental clines. The Thick-Billed Murre (Uria lomvia) is a highly philopatric colonial arctic seabird that occupies a significant environmental gradient, shows marked phenotypic differences among colonies, and has large effective population sizes. To test whether Thick-Billed Murres from five colonies along the eastern Canadian Arctic coast show genomic signatures of local adaptation to their breeding grounds, we analyzed geographic variation in genome-wide markers mapped to a newly assembled Thick-Billed Murre reference genome. We used outlier analyses to detect loci putatively under selection, and clustering analyses to investigate patterns of differentiation based on 2220 genomewide single nucleotide polymorphisms (SNPs) and 137 outlier SNPs. We found no evidence of population structure among colonies using all loci but found population structure based on outliers only, where birds from the two northernmost colonies (Minarets and Prince Leopold) grouped with birds from the southernmost colony (Gannet), and birds from Coats and Akpatok were distinct from all other colonies. Although results from our analyses did not support local adaptation along the latitudinal cline of breeding colonies, outlier loci grouped birds from different colonies according to their non-breeding distributions, suggesting that outliers may be informative about adaptation and/or demographic connectivity associated with their migration patterns or nonbreeding grounds.
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Original Article The Arctic: Glacial Refugium or Area of Secondary Contact? Inference from the Population Genetic Structure of the Thick- Billed Murre (Uria lomvia), with Implications for Management
2014Co-Authors: Anna Tigano, Martin Damus, Tim P. Birt, Jamie A. Morris-pocock, Yuri B. Artukhin, Vicki L. FriesenAbstract:Quaternary glaciations affected the distribution of many species. Here, we investigate whether the Arctic represented a glacial refugium during the Last Glacial Maximum or an area of secondary contact following the ice retreat, by analyzing the genetic population structure of the Thick-Billed Murre (Uria lomvia), a seabird that breeds throughout the North Atlantic, North Pacific and Arctic Oceans. The Thick-Billed Murre is a species of socio-economic importance and faces numerous threats including hunting, oil pollution, gill netting, and climate change. We compared variation in the mitochondrial DNA (mtDNA) control region (n = 424), supplemented by 4 microsatellite loci (n = 445), among Thick-Billed Murres sampled throughout their range. MtDNA data indicated that colonies comprise 4 genetically differentiated groups (Φst = 0.11–0.81): 1) Atlantic Ocean plus New Siberian Islands region, 2) Cape Parry, 3) Chukchi Sea, and 4) Pacific Ocean. Microsatellite variation differed between Atlantic and Pacific populations. Otherwise, little substructure was found within either ocean. Atlantic an
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philopatry morphological divergence and kin groups structuring in thick billed Murres uria lomvia within a colony in arctic canada
Journal of Avian Biology, 2011Co-Authors: G. Ibarguchi, Anthony J. Gaston, Vicki L. FriesenAbstract:Many seabirds exhibit high natal philopatry despite their extreme dispersal ability and delayed reproduction, and some exhibit phenotypic clustering in colonies and fostering or adoption of neighbouring chicks. Previous investigations of kinship in a small Thick-Billed Murre colony Uria lomvia (Alcidae) in Norway revealed high relatedness among breeders on cliff ledges. To investigate the presence of kin groups and within-colony genetic sub-structuring elsewhere, we investigated kinship within a larger Murre colony on Coats Island, Nunavut, Canada. Morphological (five characters) and genetic data (five microsatellite loci and a fragment of the mitochondrial cytochrome b gene) were analysed. Strong morphological differentiation was found among ledges. Genetic structuring was overall weak but significant at the coarse scale for males among ledges and on the east vs. the west side of the colony. Global spatial autocorrelation analyses did not detect consistent, widespread spatial patterns, although local 2D analyses provided some evidence of a tendency for larger neighbourhood sizes for females and a broad range of small to large neighbourhoods for males. Average within-ledge relatedness was low overall, but ranged widely from slightly unrelated to greater than the level of cousins in both sexes. Kin-level relationships occurred on ledges more frequently for same-sex groups than expected by chance, suggesting that recruiting breeders (especially females) avoid or are unable to settle directly adjacent to relatives particularly of the opposite sex. Behavioural studies of natal dispersal of Murres at Coats I. indicating that both sexes are highly philopatric, but that up to one-fifth of females may disperse, are concordant with this study. Overall, structuring was weaker than in Norway, and may be explained in part by genetic marker and sampling artifacts, and by the lack of genetic equilibrium suspected in the much larger Canadian Arctic colony. Natal philopatry may be an important factor driving the diversification of seabirds and kin groups in other colonies and species and may be more widespread than is currently acknowledged.
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molecular identification of a backcross between a female common Murre thick billed Murre hybrid and a male common Murre
Canadian Journal of Zoology, 1993Co-Authors: Vicki L. Friesen, William A. Montevecchi, Robert T Barrett, William S DavidsonAbstract:Reports of interspecific hybrids that are based on morphological characters are often questioned, but new techniques in molecular genetics permit reliable identification of hybrids as well as sensitive detection of introgression. As part of a larger population survey, morphology, allozymes, and mitochondrial DNA were compared among 239 Thick-Billed Murres (Uria lomvia) from five Atlantic colonies and 143 common Murres (Uria aalge) from four Atlantic colonies. One Murre possessed the morphology and electrophoretic profile of a common Murre, and the mitochondrial cytochrome b genotype of a Thick-Billed Murre. Its genetic constitution suggests that a female Thick-Billed Murre bred with a male common Murre, producing a daughter that subsequently bred with a male common Murre.
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A Review of Thick-Billed Murre Banding in the Canadian Arctic, 1950–2010
'The Arctic Institute of North America', 2014Co-Authors: Gaston, Anthony J., Robertson, Gregory J.Abstract:Banding of Thick-Billed Murres Uria lomvia in the Canadian Arctic was initiated by L.M. Tuck in the 1950s, when he visited three of the largest breeding colonies in Canada. Up to 2010, banding had been carried out at eight of the 10 major breeding colonies, with totals of more than 1000 birds banded at Coburg Island and Cape Hay, Bylot Island, in the High Arctic and at Digges Sound and Coats Island in northern Hudson Bay. Because Murres are long-lived birds, large-scale banding can continue to provide useful results for decades. A total of about 89 000 bandings in Arctic Canada resulted in 1757 usable recoveries up to 2010, the vast majority of which were birds killed by hunters in West Greenland or Newfoundland and Labrador. There was no apparent change in the large-scale geographical pattern of recoveries over the period reviewed, but the proportion of bands recovered has fallen. Several periods of higher- or lower-than-expected recoveries can be attributed to particular events: anomalous ice conditions, intensive gill-net fisheries, and oiling at sea. Thus, banding provided a useful tool not only for identifying migration and wintering areas, but also for identifying transient sources of increased mortality.Les débuts du baguage des guillemots de Brünnich Uria lomvia dans l’Arctique canadien remontent aux années 1950, sous l’égide de L.M. Tuck à l’occasion de sa visite de trois des plus grandes colonies de nidification au Canada. Jusqu’en 2010, le baguage a été effectué à huit des dix grandes colonies de nidification, pour un total de plus de 1 000 oiseaux bagués à l’île Coburg, à cap Hay et à l’île Bylot, dans l’Extrême-Arctique, ainsi qu’au détroit de Digges et à l’île Coats, dans le nord de la baie d’Hudson. Puisque les guillemots de Brünnich sont des oiseaux qui vivent longtemps, le baguage à grande échelle peut donner des résultats pendant des années. Jusqu’en 2010, les quelque 89 000 baguages effectués dans l’Arctique canadien se sont traduits par 1 757 récupérations d’oiseaux utilisables, la vaste majorité d’entre eux ayant été tuée par des chasseurs de l’ouest du Groenland ou de Terre-Neuve-Labrador. Il n’y avait aucun changement apparent dans le modèle géographique à grande échelle des oiseaux récupérés au cours de la période examinée, mais la proportion de bagues récupérées a diminué. Plusieurs périodes de récupérations plus grandes ou moins grandes que prévu peuvent être attribuées à des événements particuliers : un état anormal des glaces, la pêche intensive au filet maillant et le mazoutage en mer. Par conséquent, le baguage a représenté un outil utile non seulement pour déterminer les lieux de migration et les aires d’hivernage, mais aussi pour repérer les sources transitoires de mortalité accrue.Mots clés : L.M. Tuck, guillemot de Brünnich, Uria lomvia, chasse, baguage, population
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Age, Sex, and Telomere Dynamics in a Long-Lived Seabird with Male-Biased Parental Care
Bucknell Digital Commons, 2013Co-Authors: Young, Rebecca C., Elliott, Kyle H., Haussmann, Mark F., Kitaysky, Alexander S., Descamps Sebastien, Orben, Rachael A., Gaston, Anthony J.Abstract:The examination of telomere dynamics is a recent technique in ecology for assessing physiological state and age-related traits from individuals of unknown age. Telomeres shorten with age in most species and are expected to reflect physiological state, reproductive investment, and chronological age. Loss of telomere length is used as an indicator of biological aging, as this detrimental deterioration is associated with lowered survival. Lifespan dimorphism and more rapid senescence in the larger, shorter-lived sex are predicted in species with sexual size dimorphism, however, little is known about the effects of behavioral dimorphism on senescence and life history traits in species with sexual monomorphism. Here we compare telomere dynamics of Thick-Billed Murres (Uria lomvia), a species with male-biased parental care, in two ways: 1) cross-sectionally in birds of known-age (0-28 years) from one colony and 2) longitudinally in birds from four colonies. Telomere dynamics are compared using three measures: the telomere restriction fragment (TRF), a lower window of TRF (TOE), and qPCR. All showed age-related shortening of telomeres, but the TRF measure also indicated that adult female Murres have shorter telomere length than adult males, consistent with sex-specific patterns of ageing. Adult males had longer telomeres than adult females on all colonies examined, but chick telomere length did not differ by sex. Additionally, inter-annual telomere changes may be related to environmental conditions; birds from a potentially low quality colony lost telomeres, while those at more hospitable colonies maintained telomere length. We conclude that sex-specific patterns of telomere loss exist in the sexually monomorphic Thick-Billed Murre but are likely to occur between fledging and recruitment. Longer telomeres in males may be related to their homogamous sex chromosomes (ZZ) or to selection for longer life in the care-giving sex. Environmental conditions appeared to be the primary drivers of annual changes in adult birds
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Effects of Climate-Induced Changes in Parasitism, Predation and Predator-Predator Interactions on Reproduction and Survival of an Arctic Marine Bird
'The Arctic Institute of North America', 2013Co-Authors: Gaston, Anthony J., Elliott, Kyle H.Abstract:A detailed understanding of the processes and interactions within biological communities is needed to describe and predict the biological consequences of climate change. Global warming may affect biological communities at specific sites through changes in the species composition that follow changes in range, or through altered food web interactions caused by changes in phenology or behaviour. We describe the demographic consequences for a colonial nesting seabird, the Thick-Billed Murre (Uria lomvia), of exceptionally intense mosquito parasitism and predation by polar bears in a particular year. Increases in mosquito parasitism and bear predation are changes in behaviour rather than changes in range, and both caused unusual adult mortality and reproductive failure in Thick-Billed Murres. In the case of adult mortality, the effects of predation and parasitism were complementary, whereas in the case of reproductive failure, most birds affected by parasitism would in any case have subsequently lost their eggs to bear predation. The mosquito and bear activities had the secondary result of redirecting the attention of gulls and foxes, the usual predators of Murre eggs, towards scavenging carcasses and preying on eggs exposed by birds deserting their ledges. This diversion reduced the impact of gulls and foxes on the Murres and altered the spatial configuration of predation risk. Our observations emphasize the difficulty faced by ecologists in predicting the consequences of global warming even for simple and relatively well-studied ecosystems. Moreover, the net effect of combined parasitism and predation was much greater than reported previously, reducing overall colony productivity by 20% and increasing adult mortality by 20%. If this effect happens every year, it will have population consequences.Il y a lieu de bien comprendre les processus et les interactions qui se produisent au sein des communautés biologiques afin d’être en mesure de décrire et de prévoir les conséquences biologiques du changement climatique. Le réchauffement climatique peut avoir des incidences sur les communautés biologiques de sites spécifiques en ce sens que la composition des espèces peut être modifiée en raison de changements caractérisant le parcours naturel ou en encore, en raison d’interactions altérées à l’échelle du réseau alimentaire attribuables à des changements de phénologie ou de comportement. Nous décrivons les conséquences démographiques relatives à un oiseau de mer colonial en nidification, soit le guillemot de Brünnich (Uria lomvia), de même que les conséquences du parasitisme exceptionnellement intense des moustiques et de la prédation par les ours polaires au cours d’une année donnée. L’intensification du parasitisme des moustiques de même que la prédation par les ours correspondent à des changements de comportement plutôt qu’à des changements de parcours, et ces deux facteurs ont causé une mortalité inhabituellement élevée chez les adultes ainsi qu’une infécondité chez le guillemot de Brünnich. En matière de mortalité chez les adultes, les effets de la prédation et du parasitisme étaient complémentaires, tandis qu’en matière d’infécondité, la plupart des oiseaux touchés par le parasitisme auraient tout de même fini par perdre leurs oeufs en raison de la prédation par les ours. L’activité des moustiques et des ours a eu pour résultat secondaire de réorienter l’attention des goélands et des renards, qui sont les prédateurs habituels des oeufs de guillemot, vers la charogne des carcasses et la prédation des oeufs exposés par les oiseaux qui désertaient leurs corniches. Cette diversion a eu pour effet d’atténuer l’incidence des goélands et des renards sur les guillemots, en plus de modifier la configuration spatiale du risque de prédation. Nos observations font ressortir la difficulté à laquelle font face les écologistes en matière de prévision des conséquences du réchauffement climatique, même dans le cas d’écosystèmes simples et relativement bien étudiés. Par ailleurs, l’effet final du parasitisme et de la prédation mis ensemble était beaucoup plus grand que ce qui n’avait déjà été signalé, ce qui a eu pour effet de réduire la productivité générale de la colonie de 20 pour cent et d’accroître le taux de mortalité chez les adultes dans une mesure de 20 pour cent. Si cet effet se répétait chaque année, il aurait des conséquences sur la population
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Movements and wintering areas of breeding age Thick-Billed Murre Uria lomvia from two colonies in Nunavut, Canada
'Springer Science and Business Media LLC', 2011Co-Authors: Gaston, Anthony J., Robertson, Gregory J., Fifield, David A., Smith, Paul A., Tranquilla, Laura Mcfarlane, Montevecchi, William A., Gilchrist H. Grant, Hedd April, Mallory, Mark L., Phillips, Richard A.Abstract:The non-breeding movements of marine birds were poorly known until recently, but this information is essential to understanding the risk to different geographical populations from events on the wintering grounds. We tracked the migration routes and wintering areas of Thick-Billed Murre Uria lomvia from two breeding colonies in eastern Canada: Coats Island in northern Hudson Bay and The Minarets, Baffin Island, during the period August 2007-May 2008 using geolocation loggers. Birds from The Minarets moved south rapidly post-breeding and wintered principally off Newfoundland and southern Labrador, or between Newfoundland and southern Greenland, remaining south of 55A degrees N until at least the spring equinox. Those from Coats Island remained in Hudson Bay until at least mid-November, after which they moved rapidly through Hudson Strait to winter in southern Davis Strait and the northern Labrador Sea, mostly north of 55A degrees N. Many individuals stayed throughout the winter in areas of heavy ice cover. Adults from the two colonies appear to be completely segregated in winter and those from Coats Island probably did not enter the area of the winter hunt in Newfoundland. Unexpectedly, some birds from The Minarets wintered in waters beyond the continental slope and outside the distribution of pack ice, demonstrating that particular individuals can be wholly pelagic throughout the winter. Coats Island birds returned through Hudson Strait as soon as open water areas became available in spring. Their sojourn in Hudson Bay coincided very closely with the occurrence of areas with < 90% ice cover. In spite of the relatively large error in positions obtained from geolocation loggers, our results demonstrated the value of these devices by uncovering a number of previously unknown aspects of Thick-Billed Murre non-breeding ecology in the Northwest Atlantic. Comparison of the non-breeding ecology based on SST experienced in winter show that the winter niche is broader than hitherto assumed, demonstrating that separate populations may experience different selection in the face of climate change
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Trends in Forage Fish Populations in Northern Hudson Bay since 1981, as Determined from the Diet of Nestling Thick-Billed Murres Uria lomvia
'The Arctic Institute of North America', 2003Co-Authors: Gaston, Anthony J., Woo Kerry, Hipfner J. MarkAbstract:Trends in the composition of nestling Thick-Billed Murre diets were analyzed for the period 1980-2002 on the basis of observations of food delivered to nestlings at two breeding colonies in northern Hudson Bay. The incidence of arctic cod, sculpins, and benthic Zoarcidae decreased and the incidence of capelin and sandlance increased over the period considered. Arctic cod fell from a mean of 43% of deliveries in the mid-1980s to 15% in the late 1990s; benthic species (zoarcids and sculpins) fell from 36% to 15%, while capelin increased from 15% to 50% over the same period. July ice cover in Hudson Bay approximately halved during 1981-99. We suggest that the observed changes in diet composition reflect changes in the relative abundance of the fish species involved and that the decline in arctic cod and increase in capelin and sandlance were associated with a general warming of Hudson Bay waters, the result of ongoing climate change in the region.On a analysé les tendances dans la composition du régime alimentaire des oisillons du guillemot de Brünnich au cours de la période allant de 1980 à 2002, d'après les observations de l'apport de nourriture aux oisillons à deux colonies de nidification dans le nord de la baie d'Hudson. On a assisté, au cours de cette période, à une baisse de la fréquence de la morue polaire, du chabot et des zoarcidés benthiques, et à une augmentation de celle du capelan et du lançon. La morue polaire a chuté d'une moyenne représentant 43 % de l'apport au milieu des années 1980 à 15 % à la fin des années 1990; les espèces benthiques (zoarcidés et chabots) ont chuté de 36 à 15 %, tandis que le capelan a augmenté de 15 à 50 % au cours de la même période. En juillet, le manteau glaciel dans la baie d'Hudson a diminué de moitié environ entre 1981 et 1999. On suggère que les changements observés dans la composition du régime alimentaire sont un reflet des changements dans l'abondance relative des espèces de poissons concernées et que le déclin de la morue polaire et l'augmentation du capelan et du lançon étaient associés à un réchauffement général des eaux de la baie d'Hudson, réchauffement qui résulte du changement climatique que connaît actuellement la région
